package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * 聚合函数
 */
public class Demo7 {
    public static void main(String[] args) {
        //查看一共多少位老师
        try (
                Connection connection = DBUtil.getConnection();
                ) {
            Statement statement = connection.createStatement();
            String sql = "SELECT COUNT(*) count,AVG(salary) avg_sal " +
                         "FROM teacher ";
            ResultSet rs = statement.executeQuery(sql);
            while (rs.next()) {
                int count = rs.getInt("count");
                double avgSal = rs.getDouble("avg_sal");
                System.out.println("一共"+count+"位老师，平均工资为:"+avgSal);
            }



        } catch (SQLException e) {
            e.getStackTrace();
        }
    }
}
